Changes the tile at (x, y) to the given tile
Called on the last frame of the event
Called when the event triggers
Called every frame when the event is active.
Undoes all changed tiles
Tiles changed by this event
When the event should disappear (set to Infinity if the event should always be active)
When the event should appear
Whether this event has been triggered or not yet
Represents single thing that can appear or happen on the screen